Merge remote-tracking branch 'kwolf/for-anthony' into staging

* kwolf/for-anthony:
  virtio-blk: hide VIRTIO_BLK_F_CONFIG_WCE from old machine types
  Documentation: Warn against qemu-img on active image
  vmdk: Read footer for streamOptimized images
  vmdk: Fix header structure

Conflicts:
	hw/virtio-blk.c

4 files changed, 69 insertions, 1 deletions

diff --git a/block/vmdk.c b/block/vmdk.c
index daee4268be..bba4c61a74 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -35,6 +35,7 @@
 #define VMDK4_FLAG_RGD (1 << 1)
 #define VMDK4_FLAG_COMPRESS (1 << 16)
 #define VMDK4_FLAG_MARKER (1 << 17)
+#define VMDK4_GD_AT_END 0xffffffffffffffffULL
 
 typedef struct {
     uint32_t version;
@@ -57,8 +58,8 @@ typedef struct {
     int64_t desc_offset;
     int64_t desc_size;
     int32_t num_gtes_per_gte;
-    int64_t gd_offset;
     int64_t rgd_offset;
+    int64_t gd_offset;
     int64_t grain_offset;
     char filler[1];
     char check_bytes[4];
@@ -115,6 +116,13 @@ typedef struct VmdkGrainMarker {
     uint8_t  data[0];
 } VmdkGrainMarker;
 
+enum {
+    MARKER_END_OF_STREAM    = 0,
+    MARKER_GRAIN_TABLE      = 1,
+    MARKER_GRAIN_DIRECTORY  = 2,
+    MARKER_FOOTER           = 3,
+};
+
 static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
     uint32_t magic;
@@ -451,6 +459,54 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
     if (header.capacity == 0 && header.desc_offset) {
         return vmdk_open_desc_file(bs, flags, header.desc_offset << 9);
     }
+
+    if (le64_to_cpu(header.gd_offset) == VMDK4_GD_AT_END) {
+        /*
+         * The footer takes precedence over the header, so read it in. The
+         * footer starts at offset -1024 from the end: One sector for the
+         * footer, and another one for the end-of-stream marker.
+         */
+        struct {
+            struct {
+                uint64_t val;
+                uint32_t size;
+                uint32_t type;
+                uint8_t pad[512 - 16];
+            } QEMU_PACKED footer_marker;
+
+            uint32_t magic;
+            VMDK4Header header;
+            uint8_t pad[512 - 4 - sizeof(VMDK4Header)];
+
+            struct {
+                uint64_t val;
+                uint32_t size;
+                uint32_t type;
+                uint8_t pad[512 - 16];
+            } QEMU_PACKED eos_marker;
+        } QEMU_PACKED footer;
+
+        ret = bdrv_pread(file,
+            bs->file->total_sectors * 512 - 1536,
+            &footer, sizeof(footer));
+        if (ret < 0) {
+            return ret;
+        }
+
+        /* Some sanity checks for the footer */
+        if (be32_to_cpu(footer.magic) != VMDK4_MAGIC ||
+            le32_to_cpu(footer.footer_marker.size) != 0  ||
+            le32_to_cpu(footer.footer_marker.type) != MARKER_FOOTER ||
+            le64_to_cpu(footer.eos_marker.val) != 0  ||
+            le32_to_cpu(footer.eos_marker.size) != 0  ||
+            le32_to_cpu(footer.eos_marker.type) != MARKER_END_OF_STREAM)
+        {
+            return -EINVAL;
+        }
+
+        header = footer.header;
+    }
+
     l1_entry_sectors = le32_to_cpu(header.num_gtes_per_gte)
                         * le64_to_cpu(header.granularity);
     if (l1_entry_sectors == 0) {
diff --git a/hw/virtio-blk.h b/hw/virtio-blk.h
index 651a000b9f..f0740d01af 100644
--- a/hw/virtio-blk.h
+++ b/hw/virtio-blk.h
@@ -104,6 +104,7 @@ struct VirtIOBlkConf
     BlockConf conf;
     char *serial;
     uint32_t scsi;
+    uint32_t config_wce;
 };
 
 #define DEFINE_VIRTIO_BLK_FEATURES(_state, _field) \
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 5e6e09efb7..2a3d86f176 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -886,6 +886,7 @@ static Property virtio_blk_properties[] = {
 #ifdef __linux__
     DEFINE_PROP_BIT("scsi", VirtIOPCIProxy, blk.scsi, 0, true),
 #endif
+    DEFINE_PROP_BIT("config-wce", VirtIOPCIProxy, blk.config_wce, 0, true),
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
     DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features),
diff --git a/qemu-img.texi b/qemu-img.texi
index 77c6d0b6b0..6b42e35fe7 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -4,6 +4,16 @@ usage: qemu-img command [command options]
 @c man end
 @end example
 
+@c man begin DESCRIPTION
+qemu-img allows you to create, convert and modify images offline. It can handle
+all image formats supported by QEMU.
+
+@b{Warning:} Never use qemu-img to modify images in use by a running virtual
+machine or any other process; this may destroy the image. Also, be aware that
+querying an image that is being modified by another process may encounter
+inconsistent state.
+@c man end
+
 @c man begin OPTIONS
 
 The following commands are supported: